// Read next input byte; we do not support suspension in this module.
static int get_byte_arith(jpeg_decompress cinfo)
{
jpeg_source_mgr src = cinfo.src;
if (src.bytes_in_buffer == 0)
{
if (!src.fill_input_buffer(cinfo))
{
ERREXIT(cinfo, J_MESSAGE_CODE.JERR_CANT_SUSPEND);
}
}
src.bytes_in_buffer--;
return(src.input_bytes[src.next_input_byte++]);
}
// Convert a stream into a source manager.
public static void StreamToSourceManager
(ref jpeg_decompress_struct cinfo, Stream stream,
byte[] prime, int primeLen)
{
// Allocate a state structure and store it in "cinfo".
IntPtr buf = Marshal.AllocHGlobal(4096);
StreamState state = new StreamState();
state.buf = buf;
state.buffer = new byte [4096];
state.stream = stream;
cinfo.client_data = (IntPtr)(GCHandle.Alloc(state));
// We prime the input buffer with the JPEG magic number
// if some higher-level process has already read it.
int len;
if (prime != null)
{
len = primeLen;
Marshal.Copy(prime, 0, buf, len);
}
else
{
len = 0;
}
// Create the managed version of "jpeg_source_mgr".
jpeg_source_mgr mgr = new jpeg_source_mgr();
mgr.next_input_byte = buf;
mgr.bytes_in_buffer = (size_t)len;
mgr.init_source = new init_source_type(init_source);
mgr.fill_input_buffer =
new fill_input_buffer_type(fill_input_buffer);
mgr.skip_input_data =
new skip_input_data_type(skip_input_data);
mgr.resync_to_restart =
new resync_to_restart_type(jpeg_resync_to_restart);
mgr.term_source =
new term_source_type(term_source);
// Convert it into the unmanaged version and store it.
#if __CSCC__
IntPtr umgr = Marshal.AllocHGlobal(sizeof(jpeg_source_mgr));
Marshal.StructureToPtr(mgr, umgr, false);
cinfo.src = (jpeg_source_mgr *)umgr;
#endif
}
// Convert a stream into a source manager.
public static void StreamToSourceManager
(ref jpeg_decompress_struct cinfo, Stream stream,
byte[] prime, int primeLen)
{
// Allocate a state structure and store it in "cinfo".
IntPtr buf = Marshal.AllocHGlobal(4096);
StreamState state = new StreamState();
state.buf = buf;
state.buffer = new byte [4096];
state.stream = stream;
cinfo.client_data = (IntPtr)(GCHandle.Alloc(state));
// We prime the input buffer with the JPEG magic number
// if some higher-level process has already read it.
int len;
if(prime != null)
{
len = primeLen;
Marshal.Copy(prime, 0, buf, len);
}
else
{
len = 0;
}
// Create the managed version of "jpeg_source_mgr".
jpeg_source_mgr mgr = new jpeg_source_mgr();
mgr.next_input_byte = buf;
mgr.bytes_in_buffer = (size_t)len;
mgr.init_source = new init_source_type(init_source);
mgr.fill_input_buffer =
new fill_input_buffer_type(fill_input_buffer);
mgr.skip_input_data =
new skip_input_data_type(skip_input_data);
mgr.resync_to_restart =
new resync_to_restart_type(jpeg_resync_to_restart);
mgr.term_source =
new term_source_type(term_source);
// Convert it into the unmanaged version and store it.
#if __CSCC__
IntPtr umgr = Marshal.AllocHGlobal(sizeof(jpeg_source_mgr));
Marshal.StructureToPtr(mgr, umgr, false);
cinfo.src = (jpeg_source_mgr *)umgr;
#endif
}